Home – Home – Jornals – Siberian Journal of Forest Science 2017 number 3

This study considers a remote sensing technique for mean volume estimation based on a very high-resolution (VHR) aerial RGB imagery obtained using a small-sized unmanned aerial vehicle (sUAV) and a high-resolution photogrammetric digital surface model (DSM) as well as an innovative technology for field measurements (Trestima). The study area covers approx. 220 ha of forestland in Finland. The work concerns the entire process from remote sensing and field data acquisition to statistical analysis and forest volume wall-to-wall mapping. The study showed that the VHR aerial imagery and the high-resolution DSM produced based on the application of the sUAV have good prospects for forest inventory. For the sUAV based estimation of forest variables such as Height, Basal Area and mean Volume, Root Mean Square Error constituted 6.6 %, 22.6 and 26.7 %, respectively. Application of Trestima for estimation of the mean volume of the standing forest showed minor difference over the existing Forest Management Plan at all the selected forest compartments. Simultaneously, the results of the study confirmed that the technologies and the tools applied at this work could be a reliable and potentially cost-effective means of forest data acquisition with high potential of operational use.

The possibility to synthesize polarization response from earth covers at any desired combination of transmit and receive antenna polarizations is the significant advantage of polarimetric radar. It permits better identification of dominant scattering mechanisms especially when analyzing polarization signatures. These signatures depict more details of physical information from target backscattering in various polarization bases. However, polarization signatures cannot reveal spatial variations of the radar backscattering caused by volume heterogeneity of a target. This paper proposes a new approach for estimating volume target heterogeneity from polarimetric synthetic aperture radar (PolSAR) images. The approach is based on the analysis of a novel type of polarization signature, which we call fractal polarization signature (FPS). This signature is a result of polarization synthesis of initial fully polarimetric data and subsequent fractal analysis of synthesized images. It is displayed as a 3D plot and can be produced for each point in an image. It is shown that FPS describes backscattering variations or image roughness at different states of polarization. Fully polarimetric data of SIR-C and ALOS PALSAR at ascending/descending orbits were used for testing the proposed approach. The azimuthal dependence of the radar backscattering variations is discovered when analyzing backscattering from a pine forest. It correlates with the results of a field survey of trees branch distribution.

In the article are shown results of assessment of relationships between quantitative and qualitative characteristics of forests and morphometric characteristics of relief on an example model plot in Nanayskoe forest district of Khabarovsk Territory. The relevance of the investigation is connected with need for improvement of the system of forest evaluation operations in the Russian Federation, including with use of the landscape approach. The tasks of the investigation were assessment of relationships between characteristics of relief and characteristics of forest vegetation cover on different levels of forest management; evaluation of morphometric characteristics of relief are important for structure and productivity of forests; comparison of the results obtained through the use of digital terrain models ASTER and SRTM. Geoinformatic projects were formed for a model plot on the basis of digital terrain models and data of forest mensuration and State (National) Forest Inventory. On the basis of the developed method with use geoinformatic technologies were estimated morphometric characteristics of relief (average height, standard deviation of height, entropy, exposition and gradient of slopes, indexes of ruggedness and roughness), quantitative and qualitative characteristics of forests. The multifactor regression analysis, where characteristics of forests (as dependent variables) and morphometric characteristics of relief (as independent variables) were used, have been done. As a result of research, the set of morphometric characteristics of relief able to influence to variability of quantitative and qualitative characteristics of forests was identified. The set of linear regression equations able to explain 30-50 % of variability of dependent variables was obtained. The regression equations, obtained on base of digital terrain models ASTER and SRTM, comparable to each other in strength of relations (coefficients of determination), but includes the different sets of morphometric characteristics. The results of the study suggest the presence of relationships between characteristics of forests and morphometric characteristics of relief on different levels of forest management.

Interrelations between the dynamics of populations of small mammals and percent of the infected animals was investigated in selections from local populations in harvest areas of the coniferous forests of the Yenisei ridge. Previously, it was found that for normal spleen its index does not exceed 5 ‰. Therefore, it was considered infected individuals who have discovered exceeding this threshold. It was assumed that infectious and invasion diseases in the district of collection of materials is a basic factor, regulative a numbers. It was found that the greatest degree of contamination of infectious diseases is typical for many species groups of the forest (Myodes) and gray (Microtus) voles, lesser in shrews of the genus Sorex. These two groups showed a strong, statistically significant relationship between the dynamic of number and variation of percent of the infected animals. It is educed that the fluctuations in the number and proportion of infected voles synchronized in dark coniferous forests. On the cutting areas of different age, they take place asynchronously and with a delay as compared to base-line biotopes. Synchronization of increase of number of small mammals with morbidity is explained by the increase of frequency of contacts, both between animals at all and animals infected by materials - excrements, food bits and pieces, external parasites. The asynchronicity of dynamic of number and infection for harvest areas is explained in that the process of distribution of infections in harvest areas takes place after increases in animals number and subsequent migrations of patients of animals and moving through cutting areas. This means that the base-line forests are a source distribution of zoonotic infections in the populations of small mammals. For shrews the increase of part of the infected animals took place synchronously with dynamic of number in this group in all types of biotopes. On that basis, supposition about specificity of factor, defiant the increase of spleen for shrews is done.

In the study, based on the analysis of literary sources and the own research materials, the characteristic of the environmental situation in Taimyr is done, in connection with aerial technogenic impact of the Norilsk mining and metallurgical industrial complex. The dynamics of forest condition over the past decade in the area close to 200 km or more from the plant were evaluated. The analysis was performed taking into account the landscape structure of the territory. The progressive drying of the large areas of the northern forests since the early 80 is registered. In the article, according to the literature reviewed, the structure, dynamics and distribution of air industrial emissions of the Norilsk mining and metallurgical industrial complex «Norilsk Nickel» is analyzed and presented. Further, the authors considered the impact of air industrial emissions of Norilsk industrial region on the forest ecosystems of Taimyr. The focus is on the main forest-forming tree - Siberian larch Larix sibirica Ledeb. It is noted the complete absence of the larch undergrowth in the area of industrial pollution. Investigation of the technogenically damaged forests was carried out on the basis of dendrochronological research at six different points on different distances from the city of Norilsk, mainly to the south and east of the metallurgical plant. One study point (sparse larch community) is located 5 km north-west of Norilsk. We investigated stands of varying degrees of damage, including completely dead. It is shown, that outside the area of Norilsk mining and metallurgical industrial complex impact there were no signs of damage to the foliage of the trees and on the contrary, in the area of air pollution (Khantaiskoe Lake), forest stands are largely affected. The main damaging agent is sulfur dioxide.

In the paper, the natural water chemical composition spatial variability studies results in the mountain forest catchment are presented. It’s shown that the catchment biotic components’ impact upon water chemical composition is detected even at input as atmospheric precipitation. The input fluxes are acid, sulfate ones with high ratio of hydrogen, potassium and dissolved organic matter. Diversity of ecotopic conditions determines the further transformation of natural water chemical composition. The role of tree crowns in the transformation increases while the crown closure and stands’ age increase. According to macrocomponents transformation and rain acidity neutralization, forest associations form the sequence: mixed > coniferous > young deciduous ones. Dissolved organic carbon (DOC), potassium and calcium become the main components of water chemical composition, while sulfates dominate among anions. For vegetation period, 9-11 kg/ha of sulfates come below tree crown. Biogenic elements transport is gradually limited in soil profile at the migration stage. Sulfate-potassium composition throughfall in spruce-fir and secondary forests community transforms into sulfate-sodium-calcium. Hydrocarbonates predominate in soil water in broad-leaved-pine type of forest, and potassium output decreases 10 times. Geochemical type of river water keeps features of chemical composition of soil drained by river section. Negligible output of sulfates, hydrocarbonates and calcium from ecosystem is established for the headwaters. Negative balance of hydrocarbonates and calcium is compensated by significant input of these components with throughfall at catchments with predominantly pine-broad-leaved forest types.

Influence of existing methods and technologies of soil processing for forest crops on establishment and growth of cultivated tree species was studied. It was found that furrow plough processing of soil can interfere with the cultivated trees’ ecological peculiarities, because the furrow floor, where trees are planted, often constitutes the lower part of the turf or the upper part of the ashen-gray layers having unfavorable water-physical conditions and decreased crop-producing power. Whenever conifer trees grow on the bottom of a furrow excavated in medium and heavy clay loam, their growth is significantly decreased and accompanied by remarkable changes in morphology. Processing of shallow humus thickness soil with multiple cutter results in mixing of A₀, A₁ and A₂ (ashen-gray) layers. Consequently, the processed horizon obtains a lower amount of fertile substances than the vegetable soil on non-processed places. An apparatus for graded soil tillage, its construction, working principle and usage technology are described. The major peculiarity of the device consists in the ability not to crumbl the soil, but to shake down vegetable earth cut by subsurface plow from beneath. The technology involves removing roots and grass outside cultivated land, so that it cannot be then overgrown with weeds. It was found that exploitation of the device improves soil pulverization quality, enhances percentage of separates less than 10 mm and 10-50 mm, decreases content of the separate larger than 50 mm, and reduced specific energy output almost three-fold. Vertical displacement of control particles while soil processing with common cutter machines and the suggested device was studied. Establishment and growth of Siberian pine was determined in experimental productive cultures at different planting technologies. It was shown that under the suggested technology, forest plants furrow sowing can be done while soil processing, so that making nurseries becomes unnecessary, and cleaning, ploughing furrows, planting and further tending seedlings are not needed. Soil layers are not mixed, as within usual tillage. Rich soil layer is not withdrawn, so that germination ability of target seeds increases, and growth of seedlings in enhanced. The entire process takes much less energy compared to traditional technologies. Application of the device increases the quality of forest regeneration and reduces labor input owing to the new technology.

The article presents the results of research of grey alder Alnus incana L. stands on the territory of the Arkhangelsk Oblast within the North-taiga and Dvina-Vychegda taiga regions of the European part of the Russian Federation. The areas of grey alder stands in the period from 1978 to 2010 increased from 2.1 to 43.3 thousand ha in connection with the transfer to the forest fund of the former rural forests. Earlier forest inventory standards for this category of stands in the region were not developed. To compile a height and volume table, it was used the technique of I. I. Gusev (1971), which allow to minimize amount of sample trees. This technique is universal and can be used for other tree species. The field data collection was carried out on the territory of Kargopol, Velsk, Nyandoma, Arkhangelsk forestry units, the Kenozersky National Park and Dendrological Garden of the Northern Research Institute of Forestry. The result of the field work for the periods from 2013 to 2015 was 124 sample plots and 120 measured model trees for alder stand study. The developed tables are based on extensive field material (model trees and sample plots). Processing of field data was conducted by standard methods in forestry. Height grades’ table is used to determine the average height level of the stand. Volumes table is used to determine the growing stock levels for thickness grades. These tables meet the requirements of forestry practice, are used in the growing stock calculations. Development of height grade and volume tables based on known regularities of the homogeneous forest stands structure. Trees stands, which medium trees have the same forest inventory characteristics (g, h and f), are characterized by the same average volume for separate thickness grades, regardless of age, fullness, productivity rate and other characteristics of forest stands.

Studies were conducted in native spruce forests of the northern European Russian taiga. In each taiga subzone there were 8 permanent test sites analyzed. In biogeocenoses of test sites studied quantitative parameters of spruce trees’ as well as of deciduous species’ natural regeneration in respect to heights and diameters including measuring of undergrowth age in each gradation. The results of measurements were captured in a spreadsheet presenting quantitative parameters of natural regeneration of spruce trees and associated species in spruce biogecenoses grouped by taiga sub-zones in the forests of the European Russia. A graphic image features an example of changes in the quantity of trees in the age range of an oxalis-bilberry spruce forest. There were calculated average indices of ages for the spruce trees’ undergrowth (age) by heights gradations and by taiga sub-zones. As the height and age of undergrowth increases, its quantity on 1 ha of native uneven-aged spruce forest decreases, especially within the time period from 5 years to 30-40 years. Occurrence of deciduous species increases as high as 9 times on drawing from the southern taiga subzone to the northern one. For the subzone of southern taiga a correlation of linear indices of undergrowth height and its age is significant and positive (r = 0.67, when mr = 0.06 and t = 11.1).